Process for making oat cereal flake



Patented May 8, 1951 2,552,290

UNITED STATES PATENT OFFICE 2,552,290 PROCESS FOR MAKING OAT CEREAL FLAKE Edward F. Lilly, Chicago, and Eldor G. Rupp, Clarendon Hills, 111., assignors to-TheQuakcr Oats Company, Chicago, Ill., a corporation of New Jersey No Drawing. Application January 11, 1946, r Serial No. 640,678

3 Claims- (CI. 9980) The present invention relates to animproved cereal doughs, using flours as the starting ma form of ready-to-eat cereal of the breakfast food terial, and then making flakes from these doughs. type, and to the process of making the same. We are familiar withthe processes described by Primarily, the invention deals with the pro- Greenwood in United States Patent No. 2,011,050; duction of a crisp, moisture and water-resistant 5. by Lyons in United States Patent No. 2,116,634; blistered toasted cereal flake made from cereal by McKay in United States Patent No. 2,339,419; flours, as distinguished from flakes .hitherto by Scanlon in U. S. Patent No. 1,890,697; and by made from either the cereal grains or from cereal Proctor in British Patent No. 401,555. However, grits. The invention has particular application none of these result in blistered flakes. Where to the production of a palatable oat flake, almv any expansion occurs inthis type of product it though the invention is not limited to oat prodhas been to give a hollow flake. The Scanlon ucts, but may be employed for theproduction of and McKay patents mentioned above teach the flakes from other cereal flours, or mixtures art of producing such hollow flakes. None of thereof. these above-mentioned patents claim to produce, The essential principle involved, as will be 15 or will produce, an oat flake having the satismore fully explainedhereinafter, isthe producfactory characteristics which characterize our tion of a specially pressure-cooked and partially new product. 7 V dried dough, which, after -pe1leting and toast- The primary object of our invention is to proing; becomes converted into a blistered, crisp, duce a good blistered cereal flake which is crisp,- crunchy and non-slumping flake, which will an tender and crunchy, and retains those qualities: maintain these properties upon contact with to a substantial degree even after being immersed aqueous liquids such as milk or cream. in milk or cream for a matter of several minutes. The products of the present invention are to Another object of our inventionis to providea be distinguished from the prior artcerealflakes cereal product having a good flavor and a dellinanumber of respects, which will become ap- 2r cate friable structure. I J

parent when considering first the usual manner By means of the present invention weare able of making cereal flakes, such as corn flakes and to produce cereal flakes which are not only suthe like. Thus in the conventional process of perior in flavor, crispness, resistance to absorp: making corn or rice flakes, the procedure is as tion of moisture and keeping qualities, but; also follows: 7 can successfully compete on a'price basiswith 'The'grain or grits are cooked in a rotating other prepared cereals, cooker into which steam is injected. Thecooked In order that flakes may fulfill therequiregrains are then dried from about 33 to about 18 ments listed above, it is necessary that they be per cent moisture content, after which the parstrong, expanded and blistered. By the term tially .dried cooked cereal grains are allowed to blistered is meant that condition wherein the temper for about 16 to 20 hours to permit otherwise smooth moisture resistant surface is equalization of moisture within and between the interrupted by frequent elevations enclosing; open cereal kernels. The tempered grains are then spaces'between the two outer films or surfaces. subjected to a flaking treatment and the result- An expanded flake is onewhere an increas e in ing flakes are toasted in any suitable manner. thickness has taken place. Blistered flakes are Such a process produces satisfactory blistered necessarily expanded; however, expanded flakes flakes when applied to corn or rice. When the are not necessarily blistered. foregoing procedure, however, is appliedto wheat, We have now discovered a process of producthe resulting flakes are fragile, are not blistered, ing satisfactory ready-to-eat blistered cereal and lose body rapidly, in milk, whereas by the 45 flakes which involves changing the physical processfof this invention the flakes, are strong, structure of a cooked dough in such a manner blistered, and stand up well in milk. Oat flakes that, upon being subjected to flaking, there will produced by the conventional process are not be produced strong flakes having a continuous,- blistered, are mealy, lack crispness and crunchifused homogeneous form and possessingan im ness and when placed in milk they rapidly dis- 50 pervious film or surface, with the resultthat, integrate to a mush. In other words, such flakes upon toasting, the moisture escaping from these are entirely unsatisfactory and are unsalable, flakes is capable of forming blisters on the flakes In addition to the conventional processes for Without the formation of hollow flakes. l, making flakes, using grains as the starting ma- In order to illustratethe present invention,,th.e

terials, there have been many attempts to cook 55, following examples will be given, it being underl-.

stood, however, that these examples are not for the purpose of limitation, but rather of illustration. The percentage of the ingredients may be varied within wide limits, and other flavoring ingredients may be'added or substituted in Whole or in part for those stated. All parts are by weight.

Example I Parts by weight Oat flour 125 Salt 5 White cane sugar 5 Malt syrup Water 80 The above ingredients maybe mixed: in any order, but we prefer to place the oat flour in the mixing chamber of a heavy duty, steam-jacketed, pressure and vacuum-equipped dough mixeryto which the water is then added. The flavoring ingredients listed above, or any usual-flavoring end of the cooking period the internal pressure is released. Since rapiddrying is an essential feature of the process, the cooked dough is dried in theshortest time possible to about a 30 per cent moisture content. Asa method which is both rapid and convenient we prefer to dry the cooked dough in the-dough mixer undervacuum.

After removal of the desired amount of- Water, the cooked partially dried dough is formed into pellets by being extruded through a die having circular openings whichareroughly inch in diameter. A knife moving across the face of the die cuts the extruded material into" any desired length. The pellets are then-immediately subjected' to a flaking'treatment. Instead of extruding the dough throughadie,- one may roll thematerialinto-athin sheet between rolls and cut the thin dough into flakes of any desired Repeated extrusion of the dough atthis shape.- point'will prevent the development of blistered flakes. Flakes in the formof stars, circles, squares, diamonds, letters, etc., or combinations of these may be made in thismanner. The-resulting flakes arethen subjected to a blistering,

toasting, and expanding treatment byheating them by means of air having a temperature of between450 and 675 F. This may bedone in any suitable manner, such as by. passing-the flakes through a rotary oven or placingthe flakes on trays in-a toasting oven.

With the above improved process, we are-ableto obtain oat flakes which are strong and which stretch out into a thin, rubbery, fused structure which is characteristic of corn and rice flakes, but which hitherto it has been impossible to obtain with oat flakes. With this improved process the-amount of breakage which occurs during the flaking and toasting operations isactually lessthan that which occurs in the regular production with the usual process of corn or rice flakes.

The toasted oat flakes made by our improvedprocess are well blistered and well expanded. They are crisp and crunchy and stand up well in milk. They possess none of themealiness which characterizes oat flakesmade by former processes. The non-toasted oat flakes may havea 4 thickness of between 0.01 and 0.015 of an inch which increases about 225 per cent on toasting.

The physical treatment which is given the oat dough during the cooking, drying, pelleting and flaking steps isvery important and must be controlled. Insufficient treatment gives a flake which will not blister, while too much causes the formation of hollow flakes, which is quite undesirable, as these are either too brittle or tend unduly to float on milk or cream.

An exact time for cooking cannot be stated asthetime necessary will vary with the amount of dough. cooked. For example, when 225 pounds of dough are placed in a 50 gallon mixer, a cooking period of about minutes is required, butif theamount. of dough is reduced to 22.5 pounds and a 5 gallon mixer is used, the cooking time will have to be reduced to approximately 40minutes.

A certain amount oimixing is necessary in order; properlyto; cook such,- doughs. In the. absence :of; eflicientmixingandkneading the cooking efiect doesnotpenetrate amass of-v doughto anygreat extent,.but.is: restricted largely to the surfaces, and. the: mixing serves to expose new surthoroughly: cooked, such doughs will fail toyieldz At best they show satisfactory blistered flakes. only indicationsof blistering.

It. is quite essential, however,,that the dough be not overdeveloped because this causes formation of hollow. flakes.

We have, beenableto. limit this development to the propen degree by the-following. means:

(1), Controlling, the amount of mixing. This can be done by 'regulating. the speed of the mixingblades or by: intermittent mixing.-

(2) Cooking with the. minimum amount of moisture possiblefor adequate cooking, so that the subsequent drying that is necessary may be held to a minimum. Cooking. in an externally heated sealed cooker is. definitely superior to cooking with injected steam-because the moisture content. canbe more. carefully controlled.

(3) Vacuum drying, of the dough, with suiflcient capacity-to accomplish thedesired moisture reduction in a matter of one or two minutes. This holds to-a minimum the physical treatment of. the dough during. this part of the process.

(4) A minimumof handling in. reducing the dough to pellet or flake form.

When oat flour and water are heated,,the mixture first turns to alight brown; paste which is.

short and crumbly. At thissta-ge the cooked dough can be readilycrumbled. or broken up. into lumps. Uponzcontinuing the. pressure cooking, the doughchangesxtoaz darker brown color and becomes rubbery instead of crumbly. At this stage the dough ..does-. not: readily; break into lumps. Thisistheproper condition. for the cooked oat flour dough. for subsequent, flaking. and blister-- ing. The practical operator will soon learn to recognize that point during. the pressure cooking when the dough has been devoloped to the state to give the proper physical form and the proper rubber-ycharacteristics suitable for flaking and blistering.

Cooking underpressure'likewise seems essential. For example, when the internal pressure is kept at atmospheric' byallowing thedeveloped' steam to escape; it is impossilole to obtain blis- Instead it. stretches before breaking.

of the dough when cooked in thisv manner does not appear to improve any further after the first 20 minutes or so.

Best results are obtained by keeping the moisture content of the partiallydried dough from the cooker between 28.5 and 31.5 per cent. Low moisture content causes a diminishing of the blistering qualities. A moisture content beyond about 32 per cent causes flaking difliculties when the dough is transferred to the rolls;

In direct contrast to the previously well established cereal flakingprocesseswherein the cooked grain or grits are usually tempered for a period of about 24 hours before going to the flaking rolls, we have found that with our process, best results are obtained when no tempering takes place.

Example II A further improvement in the products of the present invention can be attained by the elimination of excess fatty materials from the cereal flour, especially in the case of oats, prior to the formation of the dough. This improvement is claimed in the copending application of Eldor G. Rupp, Serial No. 767,861, filed August 9, 1947.

Specifically, a de-fatted flour gives a flake which has longer shelf life and a better flavor. It seems as if the fat solvent removes certain constituents of the oats which impart a bitter flavor. The dough made from de-fatted oat flour is more rubbery, the flakes can be rolled thinner and still give a good blistered product. In general, flakes made from a de-fatted oat flour are more nearly like corn and rice flakes.

Using de-fatted oat flour as a base ingredient, the following is a typical example:

Parts by weight De-fatted oat flour 120 Salt 4 Sugar 4 Malt syrup Water 70 The method of mixing the ingredients is the same as described for using whole oat flour (Example I), namely the flour is placed in the mixer, water added and then the flavoring ingredients. We have found, however, that the cooking time is reduced when a de-fatted flour is used. Approximately 90 minutes cooking time was required when the whole flour was used; but when de-fatted flour was used instead, the cooking time was reduced to about 60 minutes.

For removal of the fatty material we prefer a fat solvent such as ethylene dichloride; however, any fat solvent which is reasonably volatile may be used. Other fat solvents which have been used include the volatile hydrocarbons, ethers and acetone. By the term substantially defatted oat flake we mean one containing less than about one per cent fat.

Example III As already indicated, other cereal flours may be used, preferably in admixture, to produce the blistered, toasted flakes of the present invention. Thus a flake containing both oat and corn flour may be made as follows:

By substituting a mixture comprising cat and corn flour in the weight ratio of 4 to 1, a flake was obtained similar physically to the flake produced in Example I when the procedure described 6 thereinwas followed. The corn, of course,imparted a characteristic flavor to the flake.

Other flour mixtures were also used in producing flakes with excellent results both in regard to the appearance of the resulting flake and to its flavor. 'Theiother flour. mixtures included:

In Examples IV-VII, the procedure was substantially that of Example I, the flavor of the flakes being influenced by the nature of the flour. It is of course understood that the other flavoring ingredients as shown in Example I were employed. r

The final thickness (i. e. after toasting) of the flakes, as made in accordance with the hereinabove described process, varies between 0.02 to 0.035 of an inch in thickness, averaging 0.025 of an inch. They are blistered, therefore comparable with corn flakes in that respect, but differ from the latter in being made from a flour instead of from a grit or grain. The present invention therefore places oats and wheat in a competitive position with corn flakes, producing a product similar in appearance to such flakes, as contrasted with the relatively tiny wheat flakes hitherto offered to the public. As already mentioned, direct production of oat flakes (i. e. from the oats as contrasted with flour) has been impossible. The present invention therefore represents a distinct and valuable forward step in the art.

Saving for themselves such equivalents as will occur to those skilled in the art into which this invention falls, applicants claim:

1. A process of making blistered, toasted and friable oat flakes capable of maintaining their tenderness, crispness and crunchiness after he- I ing mixed with cold aqueous fluids such as cream or milk which comprises mixing oat flour with water in proportions to form a dough, cooking said dough under pressure with simultaneous kneading until a noncrumbling coherent cooked dough is formed, then partially drying the cooked.

dough under vacuum, thereafter forming the resulting mass into flakes of a desired thickness, and toasting the flakes at an elevated temperature to produce the blistered product.

2. The process recited in claim 1 wherein the moisture content of the cooked dough is reduced to between about 28.5 and 31.5 per cent in the vacuum drying step and wherein the toasting step is effected at a temperature between about 450 and 650 F.

3. The process recited in claim 1 wherein the partially dried dough is pelleted in a single pelleting operation prior to flaking, and wherein the resuitingpeilets are flaked. without mechanical Number Name Date reworking. 135243051 Nixon Jan. 2 7,.- 1925 EDWARD F. LILLY. 1339 928 Perky Jan. 5, 1932 ELDOR G. RUPP. 1,890,697 SCafl10n DEC. 13, '1932 5 1,923,684 Perky Aug. 22 -1933 REFERENCES CITED 1,946,803 -McKay Feb. 13; 1-934 The following references are of record in the 23111050 Greenwood 1935 file of this patent: ia m fi ig,

-,'= yons ay UNITED STATES PATENTS 10 2,269,536 Kello Jan. 13; *1942 N b r 7 Na t 2;2'95,1 16= Kellogg Sept. 8, 1942 167,224 Chiozza Au 31, 1875 2,314,232 Levin Mar. 16, 1943 1,321,754 Kellogg Nov. 11, 1919 2, 9, 1 McKay Jan. 18, 1944 15364534 Lippen Jan, 4, 1921 -2-;3'88;904 -Co11atz Nbv.'13, 1945 

1. A PROCESS OF MAKING BLISTERED, TOASTED AND FRIABLE OAT FLAKES CAPABLE OF MAINTAINING THEIR TENDERNES, CRISPNESS AND CRUNCHINESS AFTER BEING MIXED WITH COLD AQUEOUS FLUIDS SUCH AS CREAM OF MILK WHICH COMPRISES MIXING OAT FLOUR WITH WATER IN PROPORTIONS TO FORM A DOU GH, COOKING SAID DOUGH UNDER PRESSURE WITH SIMULTANEOUS KNEADING UNTIL A NONCRUMBLING COHERENT COOKED DOUGH IS FORMED, THEN PARTIALLY DRYING THE COOKED DOUGH UNDER VACUUM, THEREAFTER FORMING THE RESULTING MASS INTO FLAKES OF A DESIRED THICKNESS, AND TOASTING THE FLAKES AT AN ELEVATED TEMPERATURE TO PRODUCE THE BLISTERED PRODUCT. 